Pedigree Webquest
Name
Objective – I can analyze pedigrees to determine the genetic make up of individuals
LINK 1: http://www.saburchill.com/IBbiology/chapters03/006.html
1. What information can be found on a pedigree chart?
2. Draw the symbol that represents a male. ________
3. Draw the symbol that represents a female. ________
4. What does a line in between two individuals represent? _____________________
5. How is an individual that is affected by the trait shown? _____________________
6. Describe how a pedigree chart shows the difference between parents and offspring.
7. What is a generation? How many generations are depicted in the pedigree to the upper right.
8. Look at the top pedigree. How many children does the first generation couple have? What are there sexes of the
children?
9. LINK 2: http://www.saburchill.com/IBbiology/chapters03/007.html:
A. What are monozygous twins? How are monozygous twins represented on a pedigree chart?
B. What are dizygous twins? How are they represented?
C. What is an X-linked trait?
D. What is meant by an affected individual? How is an affected person represented on a pedigree chart.
Part Two
10. Draw a pedigree chart for the following family. Nick and Jasmine are grandparents. They have 3 children,
Caroline, Crystal, and Ellen. Caroline is married to Jacob and they have a daughter named Leah. Crystal is married
to Edward and they have 3 children, Alice, Earl, and John. Ellen is married to Edward and has 2 daughters, Isabella
and Rosalie.
11. LINK 3: http://www.ygyh.org/hemo/whatisit.htm and go to “How is it inherited”? (left column)
A. How does a boy get hemophilia
B. How does a girl become a carrier?
12. If a woman is a carrier and the male does not have hemophilia,
draw a Punnett Square and indicate the possible outcome.
Part Three
Now use the information that you learned about Hemophilia to complete your pedigree chart from Part Two of this
lesson. Indicate that Nick, Ellen, John and Edward have hemophilia by shading in the symbols that represent them
in the Pedigree Chart.
13. Explain how hemophilia is inherited. Describe which parent gave John the defective allele for hemophilia and
explain how you know.
Part Four
LINK 4: http://anthro.palomar.edu/biobasis/bio_4.htm
Read further about sex-linked genetic disorders
14. What sex chromosomes are found in males?_______________________ Females?________________
15. Explain why females might carry a recessive X-linked trait, but not express it, whereas men always express
X-linked recessive traits.
16. How many human X-linked traits are known?
17. Give 3 examples of non-female anatomical traits that are located on the X chromosome.
18. What sex linked trait ran through the royal families of Europe?
19. How many genes are located on the Y chromosome?
20. How many genes located on the Y chromosome is involved in sperm production vs. cellular activities?
21. How many couples in America are infertile?______________
22. What is a significant cause of infertility in men?